Many articles of manufacture are made from different types of components that are assembled together. It is often desirable to maintain color uniformity among the various components. However, when the components are made of different types of materials, it can be difficult to provide a uniform visual appearance of the article when the components are assembled.
For example, footwear such as athletic shoes often comprise different types of materials including natural leather, synthetic leather, vinyl, fabric, foam and rubber. A different coating composition is conventionally applied to each type of substrate material. For example, one type of coating may be applied to natural leather upper components of the shoe, and another type of coating may be applied to synthetic leather upper components of the shoe. Furthermore, it is common to incorporate pigments into foam midsoles of such shoes in order to impart color to the midsole and/or to provide uniformity and/or color coordination between the upper components of the shoe and the midsole. Such use of multiple specialized coatings and pigments may result in relatively complex and costly manufacturing processes, inventory issues and may also gives rise to the need to “color match” the different coatings.
Color matching is a process by which the visual characteristics of more than one coating are “matched” such that the two or more coatings give the same or substantially same appearance. Color matching can be desired when, for example, two different substrates on the same article of manufacture are coated with two different coatings. Color matching can also be desired when trying to identify a coating that matches a previously coated article or component. For example, automotive body shops often paint repaired portions of autobodies with coating compositions selected to match the color of the original autobody paint; such color matched coatings often have different compositions from the original coatings, and may comprise significantly different types of coatings such as air-cured versus heat-cured coatings.
While color matched components may have substantially the same appearance in some viewing and illumination conditions, they may not maintain the same appearance when the viewing angle is changed, when the spectral distribution of the light source is changed and/or when the coatings have aged. For example, some color matched components may have the same appearance in daylight conditions, but may not match under fluorescent and/or incandescent lighting. When a color match is dependent on illumination or viewing condition, the match is termed conditional or “metameric”.
It would be desirable to provide a coating composition capable of coating various different types of substrates of an article of manufacture while eliminating the need to do color matching.